Effects of molding curing temperature and pressure on the mechanical properties of carbon fiber reinforced plastics

Abstract This paper investigates the effects of different curing temperatures, early stage and late‐stage curing pressures on the mechanical properties of carbon fiber reinforced plastics, as well as the changes in stress and heat flow at different curing temperatures. Additionally, the microstructure and interfacial properties of the composites under various curing conditions are also examined. Experimental results show that curing temperature has a greater impact on the Young's modulus, while curing pressure significantly affects the tensile strength. When the curing temperature is set to 140°C (close to the gelation temperature), the material exhibits better performance, with improved resin infiltration into the fibers and more resin residue on the fibers. Isothermal differential scanning calorimetry test heat flow curves indicate that the resin crosslinking is more complete. However, as the curing temperature increases further, the performance of the material decreases. Increasing the early‐stage curing pressure significantly improves performance, with the best results at 0.4 MPa; beyond this pressure, the performance starts to decline. The increase in late‐stage curing pressure also enhances performance. In conclusion, optimizing curing parameters can significantly improve the mechanical properties and interfacial quality of carbon fiber composites, providing important reference for the process optimization of high‐performance composite materials. Highlights Optimized temperature and pressure improve the mechanical properties of CFRP. DSC and FBG sensors monitor resin crosslinking and stress changes during curing. Curing temperature and pressure affect resin infiltration and bonding.